There is absolutely nothing even remotely like "100% reliability" in firearms. Anyone who thinks there is, is kidding themself.
I overheard a guy, who shoots a box-stock Glock 17 in USPSA competition, that he got rid of his 1911's because he didn't like putting-up with their finicky behavior and cost. He said he had put 10,000 rounds through his Glock, without a malfunction. This guy is deluded; he shoots in my squad almost every weekend, and his gun pukes on him almost every weekend. I'll call that "100% reliability of the mind" - even if it ain't true, keep telling yourself that.
I'm working on one of those costly/finicky 1911's, and was feeling pretty good about my project, having had one failure to feed in 500 rounds of range-brass reloads (this gun will replace a gun that has had one FTF in maybe 3000 rounds). Then, on the last stage of the day, my gun turned into a single shot. I had to "tap" the butt (SLAM is more like it) to urge each and every round up the feedramp, on a 28-round stage. Took the gun home, and it flawlessly cycled five different rounds through five different mags. That's reality. Any mechanical device, regardless of how it worked yesterday, or five minutes ago, can fail; be prepared for it.